Fluid pump apparatus and system

ABSTRACT

A pump apparatus and system wherein a single piston in a single cylinder produces positive pumping action in both of its reciprocating movements into a single-output outlet at one end of said cylinder. A valving system incorporated into the piston itself establishes communication of the pumping medium between one side of the piston and the other within the confines of the single cylinder. Suction of fluid into the cylinder is produced by said piston in one direction only of its rectilinear movement through a one-way valve at the other end of the cylinder. When constructed in conjunction with a vacuum-operated diaphragm for operating the piston, liquid pressure in the cylinder is utilized also to ensure a fluidtight seal between the cylinder and the adjacent vacuum chamber housing the diaphragm.

United States Patent Primary Examiner-Robert M. Walker Att0mey-l. Jordan Kunik ABSTRACT: A pump apparatus and system wherein a single piston in a single cylinder produces positive pumping action in both of its reciprocating movements into a single-output outlet at one end of said cylinder. A valving system incorporated into the piston itself establishes communication of the pumping medium between one side of the piston and the other within the confines of the single cylinder. Suction of fluid into the cylinder is produced by said piston in one direction only of its rectilinear movement through a one-way valve at the other end of the cylinder. When constructed in conjunction with a vacuum-operated diaphragm for operating the piston, liquid pressure in the cylinder is utilized also to ensure a fluidtight seal between the cylinder and the adjacent vacuum chamber housing the diaphragm.

FLUID PUMP APPARATUS AND SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a novel pump for use in liquid fluid 5 systems in automotive fields and for other applications where a practically pulsefree supply of fluid under pressure is required or desired. In the context of pumping gasoline fuel for automotive engines, the pump of the present invention, in lo conjunction with a vacuumpowered oscillating diaphragm, is intended to replace the previously utilized mechanical pumps which are located at or on the engine and which frequently produce the undesirable phenomenon of vapor lock." Such apparatus makes possible a variablevolume pumping device which automatically pumps only the amount of gasoline that is being consumed in contrast to electric fuel pumps which pump minimum fuel continuously and which require a bypass arrangement for returning a major portion of the gasoline through a pressure relief valve from the engine to the fuel tank whereby a part of this gasoline is vaporized and involves problems of preventing the vaporized gasoline from passing into the atmosphere.

The apparatus of the present invention may also be utilized to pump hydraulic fluid for such devices as shock absorbers where pressures of up to 2,000 p.s.i. may be achieved.

In the context of pumping air or gas, the device of the present invention, with slight modification, may be used to operate such accessory automotive equipment as leveling devices, shock absorbers, windshield wipers, window controls, onoff locks, seat adjustment controls, tireinflating apparatus, and the like. The apparatus herein may also be used for pumping freon gas or the like to prove refrigeration for automobiles, trucks, trailers, boats, as well as stationary equipment of various types that require fluid pressure supplies and controls.

2. Description of the Prior Art The present invention constitutes an improvement over prior art devices such as disclosed in U.S. Pat. No. 3,339,830, and US. Pat. No. 3,544,239. In said prior art, pumps are discussed where each individual piston in either the singleor doublepiston embodiments produces a compression stroke only in one direction thereof. These prior art devices would not be useful in the context of pumping liquid materials where a steady flow of liquid is required without any appreciable pulsations that are otherwise permissible where storage tanks are to be filled with compressed air or gas.

SUMMARY OF THE INVENTION In order to overcome the disadvantages and deficiencies of prior art apparatus, the present invention comprises the novel pistoncylinder structure and system of operation wherein the piston produces a fluid pressure stroke in each of its opposite rectilinear motions so that positive pressure is continually maintained in said line and pulsation of fluid flow is considerably minimized or practically eliminated.

An important feature of the invention is the provision of a valving means on the piston which permits the latter to produce a pressure stroke in each of its opposite reciprocating movements, with the fluid output occurring at one end only of said cylinder during each of said strokes. Connected to one side of the piston is a comparatively thick piston rod, which during one of the piston pressure strokes in each cycle of two, enters into the output end portion cylinder thereby reducing its capacity and causing excess fluid to be expelled into the pump output notwithstanding the fact that the piston at that time is moving away from the output end of the cylinder. By the novel combination of the valving means on the piston and the automatic diminution of the cylinder capacity by the entrance of the piston rod into the cylinder, the output end portion of the cylinder is continuously maintained full of fluid during each opposite stroke of the piston, thereby ensuring positive pressure in a line linking the pump to the serviced apparatus, particularly when the fluid is a comparatively noncomprcssible liquid such as gasoline, oil, water, or the like. 75

Also, by continuously maintaining positive fluid pressure in the output area of the cylinder during each of the opposite strokes of the piston, said fluid pressure is utilized to ensure the integrity of a fluidtight seal between said cylinder and an adjacent vacuum chamber when the piston is connected to a vacuumoperated oscillating diaphragm.

The cylinder has an inlet end and outlet end, and the piston moves reciprocable between one end and the other within said cylinder by means of a piston rod extending through the outlet end portion of said cylinder. The piston produces a suction stroke only in the direction of movement from the inlet end toward the outlet end. The inlet end of the cylinder has a oneway valve to enable the piston to produce a pressure stroke when it moves toward the inlet end. By providing a piston rod having an appreciable mass, its movement into the cylinder results in increasing displacement of fluid on the outlet side of the piston while, at the same time, the bypass valve on said piston transmits fluid from the inlet side of the piston to the outlet side of the piston to bring about an excess amount of fluid in said outlet side which is thereby transmitted under pressure to apparatus to which the outlet end of the cylinder is connected.

Another feature of the invention is the provision of a novel valving system for alternatively producing negative pressures on opposite sides of the vacuum diaphragm. The valving system comprises a cylinder within which is located a spool valve having three spacedapart O- rings. The reciprocating movement of the spool by linkage with the reciprocating diaphragm provides for the alternating opening and closing of separate ports to opposite sides of the vacuumoperated diaphragm, said valve cylinder being connected to the manifold of an automotive engine or the like where negative pressure is produced. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is, in part, a vertical onehalf central section of the pump of the present invention showing the movable diaphragm and pump element located at or near the end of their respective downward strokes, some parts being shown in elevation and some parts in dotted outline;

FIG. 1B is comparable to FIG. 1A and shows the opposite onehalf central section view of the pump wherein the movable diaphragm and pumping element are located at or near the end of their respective upward strokes, it being understood that the vacuum valve control element located on top of the vacuum housing extends over both FIGS. 1A and 1B, and is illustrated as being in a position where the pumping elements are at the ends of their respective downward and upward strokes;

FIG. 2 is a top view of the apparatus shown in FIGS. 1A and 1B, some parts being broken away;

FIG. 3 is a side elevation of the apparatus shown in FIG. 2, some parts being shown in dotted outline;

FIG. 4 is a fragmentary partial central section view of the upper portion of the vacuum housing showing the vacuum control elements on the exterior of the housing being located in a position where the pumping elements are at the bottom of their respective downward strokes, some parts being broken away and some parts being shown in elevation;

FIG. 5 is a view taken on line 5-5 of FIG. 4, some parts being shown in elevation; and

FIG. 6 is a fragmentary view of a portion of the apparatus showing a valve embodiment for adapting the apparatus to the pumping of air or gas.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1A and 1B of the drawings each show respective complementary halves of the apparatus herein in vertical section, wherein like numbers refer to similar parts which are shown in different operational locations in said respective Figures. Except for elements that are external to the vacuum chamber and the pressure cylinder, those components shown within said vacuum chamber and pressure cylinder may generally be assumed to be substantially circular in horizontal cross section.

Referring now to the drawings in detail, the housing of the apparatus comprises a pair of bell sections 11 and 12, each having annular mating flanges l3 and 14, respectively, secured together by means of a plurality of spacedapart screws 16 in circular array. Clamped fast between flanges l3 and 14 is the peripheral edge portion of a flexible diaphragm 17 which is movable within the spaced enclosed by bell sections 11 and 12 and which divides and separates said spaced into two chambers 18 and 19 which vary inversely in volume according as said diaphragm moves in one vertical direction or the other. Bell section 11 has a top end wall 21 having a central axial aperture 22 which accommodates a reciprocating control rod 23 therein. End wall 21 has an integrally formed raised collar 24 surrounding rod 23 and which encloses an axial aperture in which is positioned O- ring 26 which is held captive by a spider retaining ring 27 secured frictionally within collar 24. O- ring 26 serves as a one-way vacuum seal for chamber 18.

Bell section 12 has an end wall 28 that serves as a partition between vacuum chamber 19 and the piston assembly of the apparatus. Partition 28 has a central axial aperture 34 through which tubular shaft or piston rod 36 moves reciprocably, there being a slight clearance between said rod and said aperture. Mounted on the upper and lower surfaces of the central portion of diaphragm 17 are respective circular clamp plates 37 and 38, said clamp plates being secured together by means of threaded nut 43 engaging the interior threads at the upper end of rod 36. The lower portion of rod 23 extends freely longitudinally with wide clearance through axial aperture 46 in rod 36. The vertical reciprocating motion of diaphragm 17 imparts a corresponding reciprocating motion to piston rod 36.

INtegrally formed on the lower surface of partition 28 of bell element 12 is a downwardly extending collar 47 coaxially aligned with aperture 34. Formed centrally within collar 47 is an annular recess 48 accommodating a somewhat loosely fitting O- ring 49 which serves as a seal between partition 28 and rod section 36. O- ring 49 is held captive within recess 48 by means of a washer 51 whose inside diameter provides a wide clearance for rod 36, thereby permitting free flow of fluid therethrough. Washer 51 is secured in position by a spider retaining ring 52.

Threadably or otherwise connected to the lower end of control rod 23 is a nut 56 which moves reciprocably within aperture 46 in rod 36. The downward motion of diaphragm 17 and nut 43 causes the latter engage nut 56 whereby control rod 23 is moved downwardly. During the upward motion of rod 36, the bottom floor of aperture 46 in rod 36 engages nut 56 to produce the upward motion of control rod 23.

Connected to the lower end of collar 47 is a pump assembly which comprises a circular cylinder 57 which has intermediate its upper and lower ends an integrally formed, outwardly extending annular flange 58 connected to collar 47 by means of a plurality of spacedapart bolts 59 in circular array. The upper portion of cylinder 57 extends partially into the interior of the space bounded by the annular portion of collar 47. A part of the exterior surface of cylinder 57 extending into collar 47 mates with a close fit therewith while the upper end portion of cylinder 57 has an inwardly sloping annular beveled surface 61 whereby the latter is spaced apart from the interior wall of said collar. The upper end of cylinder 57 is spaced apart from the upper end of the interior recess formed by collar 47. The upper surface of flange 58 has an annular recess 62 which accommodates O- ring 63 to form a fluidtight seal between said flange 58 and said collar 47 thereby preventing leakage between the exterior and interior of cylinder 57 at that juncture.

Collar 47 has a laterally extending threaded aperture 64 which accommodates the threaded butt 66 of a tubular fitting 67, the central aperture or channel 68 of which communicates with the upper end portion of the interior of cylinder 57. Fitting 67 has a threaded extension 69 to which suitable tubing may be attached for transmitting fluids under pressure to devices which are to be serviced, as described hereinbefore.

By spacing the upper end of cylinder 57 slightly apart from the horizontal surface of the recess formed by collar 47, and by providing for the beveled surface 61 at the upper portion of said cylinder, the upper end of said cylinder is provided with a suitable outlet in the form of fitting 67 while, at the same time, the entrance of piston rod 36 into said cylinder is unimpeded by any interfering outlet arrangement.

integrally formed on the bottom end of rod 36 is a downwardly extending threaded butt 71 to which is threadably connected a piston 72 which is movable reciprocably within cylinder chamber 73 in cylinder 57. The outside diameter of piston 72 is slightly smaller than the inside diameter of cylinder chamber 73. Piston 72 has a peripheral annular recess 74 which accommodates an O- ring 76 made of suitable resilient material. Near the top periphery of piston 72 there is formed a plurality of spacedapart apertures 77 in circular array which communicate with recess 74 to provide for by pass of fluid during the downward stroke of piston 72 when 0- ring 76 is urged against peripheral flange 78 of said piston (FIG. 1A). During the upward pressure stroke of piston 72, O- ring 76 is urged downwardly against the lower peripheral flange 79 of said piston (FIG. 1B) whereby the latter compresses fluid into the upper portion of chamber 73. During the downward stroke of piston 72, O- ring 76 is urged against flange 78 whereby fluid in cylinder chamber 73 passes freely from the bottom side of said piston through apertures 77 to the upper side of said piston into the upper portion of said chamber.

The lower end of cylinder 57 is enclosed by a fluid inlet and check valve assembly which comprises a ring plug 81 secured in position by a suitable washer 82. Plug 81 has an integrally formed, downwardly extending collar 83 which is engaged by a threaded inlet fitting 84 whose lower end is connectable to a suitable fluid inlet supply source.

Located in the central aperture of plug 81 is a check valve assembly which comprises a floating block 86 which has intermediate its ends an integrally formed, outwardly extending flange 87. The central aperture of plug 81 has an annular sloping surface 88 against which there is positioned a resilient O- ring 89 which surrounds the lower portion of block 86 beneath flange 87. Threadably connected to the central portion of block 86 is a rod 91 which extends downwardly into the axial aperture of inlet fitting 84 and which serves to stabilize the reciprocating movement of said block. Block 86 is held captive within the interior of ring plug 81 by means of a spider ring 92 whose inside diameter is somewhat smaller than the outside diameter of flange 87.

During the downward movement of piston 7 2, fluid pressure in the lower portion of chamber 73 causes the downward movement of block 86 whereby flange 87 causes 0- ring 89 to bear against beveled surface 88 to seal the bottom of chamber 73 and to prevent fluid from passing out of the lower end of cylinder 57. During the upward movement of piston 72 which produces a negative pressure within the lower portion of chamber 73, by virtue of O- ring 76 acting as a one way fluid seal or valve between flange 79 and the inner surface of cylinder 57, block 86 as well as O- ring 89 are caused to move upwardly thereby permitting fluid to enter through inlet fitting 84 and past 0- ring 89 to enter into the lower portion of chamber 73.

During the upward stroke of piston 72, fluid is being compressed in the upper portion of chamber 73 and is caused to pass outwardly through channel 68 in fitting 67. This same fluid pressure in the upper portion of chamber 73 also exerts pressure against 0- ring 49 whereby the latter produces a sealing action between bottom wall 28 and rod 36. 0- ring 49 also performs its sealing function during the downward stroke of piston 72 by virtue of negative pressure being induced in chamber 19 as well as by fluid pressure obtaining within the upper portion of cylinder chamber 73.

integrally formed with or otherwise mounted on the external surface of wall 21 and on a boss of bell section 11 is a tubular valve housing 101, the left end of which is open to the atmosphere. Movable reciprocably within valve housing 101 is a valve element generally designated 103 and comprising an elongated valve stem 104 having integrally formed or otherwise mounted thereon spacedapart annular flanges 106, 107, and 108, each of said flanged having annular U-shaped recesses accommodating 0- rings 109, 111, and 112, respectively. The uniform outside diameter of flanges 106, 107, and 108, is slightly smaller than the inside diameter of chamber 113 of valve housing 101, while the uniform outside diameter of 0- rings 109, 111, and 112, is slightly greater than the inside diameter of said chamber whereby each 0- ring acts as an airtight seal to prevent leakage from one side of said O- ring to the other. The left end portion of valve stem 104 has an axial recess 114, the outer end of which communicates with the atmosphere. Located between flanges 107 and 108 is a transverse aperture 115 which intersects the inner end portion of recess 114.

Mounted intermediate the ends of valve housing 101 and secured thereto by nut 116 (FIG. 2) is a laterally extending tubular nipple 117 which communicates with chamber 113 in housing 101. Nipple 117 is connectable by a tube or suitable flexible hose to the manifold of an automotive engine or the like which produces negative pressure.

Formed in the boss portions of the left side of bell section s 11 and 12 are aligned portions of channel 118 which by way of port 119 establishes communication between vacuum chamber 19 and chamber 113 of valve housing 101. See FIG. 1A. A suitable aperture is formed in the flange portion of diaphragm 17 to establish open communication between the two portions of channel 1 18. A port 121 is also formed in wall 21 of bell section 11 to establish communication between vacuum chamber 18 and chamber 113 of valve housing 101.

Referring to FIGS. 1A and 1B, the vacuum valve mechanism together with the linkage connecting it to rod 23 represents the condition of the apparatus where both control rod 23 and vacuum diaphragm 27 have just arrived at their upper limits as shown in FIG. 1B. The next succeeding action whereby negative pressure induced through nipple 117 and exerted through port 119 and channel 118 will draw diaphragm 17 to its lowermost position as shown in FIG. 1A.

It will be noted that when valve stem 104 is in the position as shown in FIG. 1A, flanges 106 and 107 straddle port 119, and since said flanges also straddle the aperture of nipple 117, negative pressure induced by the apparatus connected to said nipple will cause negative pressure to be induced in vacuum chamber 19 whereby diaphragm 17 will be urged downwardly. While diaphragm 17 moves downwardly, atmospheric air will be entering chamber 18 by way of port 121, transverse aperture 115, and axial recess 114 in valve stem 104. It will be noted that O- ring 111 acts as a seal between ports 119 and 121 during the downward movement of diaphragm 17.

In FIG. 4, control rod 23 and diaphragm 17 are shown as having just reached their lowermost positions. With vacuum valve 103 at its rightward position, negative pressure will next be induced through nipple 117 to create negative pressure through port 121 in vacuum chamber 18 in order to urge the diaphragm upwardly again to its previous position as shown in FIG. 1B.

When valve stem 104 is in the position as shown in FIG. 4, 0- rings 109 and 111 straddle port 121 as well as the aperture of nipple 117 whereby negative pressure is induced in vacuum chamber 18 thereby causing diaphragm 17 to move upwardly. In this position of valve stem 104, 0- ring 109 isolates port 121 from port 119 whereby atmospheric air entering through the open left end of housing passes through channel 118 into chamber 19. Thus, the reciprocating movement of valve element 103 brings about the alternating vacuum action in chambers 18 and 19 to produce the reciprocating movement of diaphragm 17. When negative pressure is being induced in chamber 18, O- ring 26 is urged downwardly by said negative pressure to act as an airtight seal notwithstanding the upward movement of control rod 23 which is in sliding engagement 7 with said O- ring.

The movement of valve 103 to the right is limited by a ring plug 122 mounted fast in the end of valve housing 101, the inner end of said ring plug forming a shoulder against which flange 108 abuts as shown in FIG. 4.

lntegrally formed or otherwise mounted on the top of wall 21 of bell section 11 is a pair of spaced apart, upwardly extending posts 123 which support a-rotatable pivot pin 124 therebetween. See FIGS. 1B, 2, 4 and 5. Mounted fast on the central portion of pin 124 by means of a setscrew 126 is a sleeve 127 having a pair of integrally formed spaceapart fingers 128 which extend on either side of control shaft 23. Mounted fast on control shaft 23 is a sleeve 129 having a pair of integrally formed flanges 131 between which fingers 128 are held captive. The upward movement of control rod 23 causes lower flange 131 to move fingers 128 upwardly, while the downward movement of said rod causes upper flange 131 to move fingers 128 downwardly.

Mounted fast on pin 124 by means of setscrews 132 are sleeves 133, the latter being located on both sides of sleeve 127. Sleeves 133 each have an integrally formed leg 134 both of which support near their outer ends a pin 136, located and movable longitudinally within slots 137 near the ends of a pair of spacedapart link bars 138, the other ends of which have angled bracket portions 139 that are pivotally connected to the end of valve stem 104 by means of pin 141. By means of the foregoing linkage, the vertical reciprocating movement of control rod 23 is translated into horizontal reciprocating movement of valve stem 104.

Snap action operation of control rod 23 and of valve element 103 is accomplished by the provision of a pair of spacedapart posts 142 which support a pin 143. Pin 143 is located within an elongated slot 144 near one end of a link bar 146, the other end of which is pivotally connected by means of pin 147 near the outer end of an arm 148 integrally formed on sleeve 127.

Coiled around link bar 146 is a spring 149, one end of which bears against pin 143, the other end of which bears against a ring 151 mounted fast on link bar 146. Spring 149 acts resiliently to urge the pivoting assembly of fingers 128 and leg 134 to move by snap action into either of two opposite positions as shown in FIGS. 1A and 4 on the one hand, and FIGS. 2 and 3, on the other hand.

Mounted on each post 142 and extending leftwardly thereof is a stop element 152 made of a resilient material such as rubber or the like which acts as a shockabsorbing abutment fora respective link bar 138.

By means of the foregoing linkage, vertical reciprocating movement of control rod 23 and of diaphragm 17 is coordinated with the horizontal movement of valve element 103 which controls the alternating vacuum operation of said diaphragm as well as the reciprocating pumping movement of piston 72 connected to said diaphragm by means of rod 36.

In operation, in the embodiment shown in FIGS. 1A and 1B, the upstroke of piston 72 exerts pressure upon liquid in the upper portion of piston chamber 73 to cause said liquid to flow over the upper outlet end of said chamber and thence outwardly through channel 68 of fitting 67. During the same upstroke, suction is exerted below piston 72 to cause fluid to flow from inlet fitting 84 into the lower portion of chamber 73 to fill the latter with fluid. On the succeeding downstroke of piston 72, the fluid beneath said piston is formed through annular recess 74 and upwardly through apertures 77 of piston 72, since the inlet port to the bottom of chamber 73 is at that time closed off by liquid pressure in said chamber acting upon valve element 86 and O- ring 89.

It will be observed that the diameter of piston rod 36 is fairly large, and when it enters into cylinder chamber 73 it occupies a large volume thereof thereby reducing its capacity and limiting the amount of fluid that can enter into the upper portion of said chamber from the lower portion thereof as piston 72 moves downwardly. Accordingly, there is a differential in liquid displacement between the downwstroke of piston 72 5 and its upstroke.

During the upstroke of piston 72, the bottom portion of chamber 73 becomes completely filled with liquid, while during the same upstroke liquid above piston 72 is forced outwardly through channel 68 of outlet fitting 67. During the succeeding downstroke of piston 72, while the inlet valve 86 seals off the inlet end of chamber 73, the amount of liquid that is caused to flow from the bottom of chamber 73 to the upper portion thereof is greater in volume than the capacity of said upper portion that has been reduced by piston rod 36, whereby the excess liquid is, of necessity, urged outwardly again through channel 68 of outlet fitting 67. Therefore, a positive fluid pressure is continually maintained through outlet fitting 67 during both the upstroke and downstroke of piston 72. This salient feature of the invention is accomplished by providing a comparatively large diameter of piston rod 36 to which the upper side of piston 72 is connected. The comparative diameters of piston rod 36 and of piston 72 are matters of choice depending upon the size of cylinder chamber 73, the apparatus for which the present pump is intended to serve, the required work output, the available vacuum power, and other variables that are ancillary to the teachings of the present invention. By reason of the foregoing structural arrangement, a continuous positive pressure is maintained for the output of this pump, thereby resulting in the continuous maintenance of a solid liquid line to the apparatus which is to be serviced and which is connected to outlet fitting 67. By this means pulsating effects in the output of the pump are greatly diminished or virtually eliminated.

Since there is positive fluid pressure always present in the upper portion of chamber 73 during both the upstroke and downstroke of piston 72, said pressure always exerts sufficient force upwardly against ring 49 to maintain a fluidtight seal between vacuum chamber 19 and cylinder chamber 73. The positive fluid pressure in the upper portion of cylinder 73 which is exerted during the downstroke of piston 72 is sufficient to cause 0- ring 49 to perform its upward sealing action notwithstanding the fact that piston rod 36 is moving downwardly. The upward fluid pressure force upon 0- ring 49 is greater than the downward friction force exerted by piston rod 36 against said O- ring.

It is understood that the words upstroke and downstroke as they pertain to piston 72, indicate the direction of traverse in the context of the vertical position of the apparatus shown in FIGS. 1A AND 18. Manifestly, the apparatus may be installed in any one of a number of different positions in automotive vehicles or the like but the orientation of up and down of piston 72 is in relation to diaphragm 17.

In the immediately foregoing description, the apparatus herein operates to pump comparatively noncompressible liquids such as gasoline fuel, water, oil, or the like. The device herein is also adaptable for pumping compressible gases such as air, freon, and the like with the slight modification thereof as illustrated in FIG. 6.

Instead of a simple, open channel fitting 67 of FIG. 1A, there is provided a tubular valve housing 161, the inner end of which is threadably inserted into aperture 64 with a suitable 0- ring 162 located in a suitable recess for providing a leaktight seal therebetween. Valve housing 161 has a valve chamber 163 into which is threadably inserted the inner end of a tubular adapter 164 with a suitable O- ring 166 being pro vided therebetween for producing a leaktight seal. Located in valve chamber 163 is a movable valve element 167 having an outwardly extending annular flange 168 which serves as an abutment for O- ring 169 which can bear against an annular sloping valve seat 171. Valve element 167 is normally urged into a closing position by means of spring 172, one end of which beats against flange 168, the other end of which bears against an annular shoulder 173 formed in the interior of adapter 164. The assembly of valve member 167, O- ring 169, and spring 172, forms a oneway check valve to retain gas that has been pumped into the apparatus to which the outer end of adapter 164 has been connected. The check valve prevents diminution of pressure within cylinder chamber 73 during the pumping action of piston 72, but permits passage of fluid outwardly through adapter 164 connected by suitable tubing to apparatus served by the pump. The strength of spring 172 is selected to provide oneway outward flow only of fluid from the pump to the attached apparatus when its force is overcome by the force of fluid pressure from the pump.

Although the present invention has been described with reference to particular embodiments and examples, it will be apparent to those skilled in the art that variations and modifications can be substituted therefore without departing from the principles and true spirit of the invention. The abstract given above is for the convenience of technical searchers and is not to be used for interpreting the scope of the invention or claims.

I claim:

1. A vacuumoperated liquid pump comprising a housing, a vacuum chamber in said housing, a vacuumoperated diaphragm within said vacuum chamber, a liquidpumping chamber in said housing on one side only of said vacuum chamber, a partition between said pumping chamber and said vacuum chamber, a piston movable reciprocably within said pumping chamber, a rod connecting said piston to said diaphragm through said partition, outlet means at one end of said pumping chamber, inlet means at the other end of said pumping chamber, valve means on said piston causing the latter to produce a compression stroke in each of its reciprocating movements and to produce a suction stroke only during its movement from the inlet end of said pumping chamber to its outlet end to cause the continuous emission of a substantially pulsefree liquid output from said outlet means.

2. A system according to claim 1 and further comprising a resilient seal between said vacuum chamber and said cylinder through which said rod moves, said seal performing its sealing function under liquid pressure from said cylinder during both reciprocating pressure strokes of said piston.

3. A system according to claim 2 wherein said oscillating means comprises a reciprocating diaphragm which divides said housing into two vacuum chambers which are alternately subjected to negative pressure, a reversing valve on said housing for controlling the induction of negative pressure alternately in said respective vacuum chambers, and a linkage connected between said diaphragm and said valve for coordinating the movement of said valve with said diaphragm.

4. A system according to claim 1 and further comprising a oneway valve on the inlet end of said cylinder and a oneway valve on said piston, said piston valve permitting bypass of liquid when said piston moves from said outlet end toward said inlet end and preventing bypass of liquid when said piston moves from said inlet end toward said outlet end. 

1. A vacuum-operated liquid pump comprising a housing, a vacuum chamber in said housing, a vacuum-operated diaphragm within said vacuum chamber, a liquid-pumping chamber in said housing on one side only of said vacuum chamber, a partition between said pumping chamber and said vacuum chamber, a piston movable reciprocably within said pumping chamber, a rod connecting said piston to said diaphragm through said partition, outlet means at one end of said pumping chamber, inlet means at the other end of said pumping Chamber, valve means on said piston causing the latter to produce a compression stroke in each of its reciprocating movements and to produce a suction stroke only during its movement from the inlet end of said pumping chamber to its outlet end to cause the continuous emission of a substantially pulse-free liquid output from said outlet means.
 2. A system according to claim 1 and further comprising a resilient seal between said vacuum chamber and said cylinder through which said rod moves, said seal performing its sealing function under liquid pressure from said cylinder during both reciprocating pressure strokes of said piston.
 3. A system according to claim 2 wherein said oscillating means comprises a reciprocating diaphragm which divides said housing into two vacuum chambers which are alternately subjected to negative pressure, a reversing valve on said housing for controlling the induction of negative pressure alternately in said respective vacuum chambers, and a linkage connected between said diaphragm and said valve for coordinating the movement of said valve with said diaphragm.
 4. A system according to claim 1 and further comprising a one-way valve on the inlet end of said cylinder and a one-way valve on said piston, said piston valve permitting bypass of liquid when said piston moves from said outlet end toward said inlet end and preventing bypass of liquid when said piston moves from said inlet end toward said outlet end. 